A sensitive electrochemical lead ion (Pb(2+)) sensor based on carboxylic acid group functionalized multi-walled carbon nanotubes (MWNTs-COOH) and direct electrodeposited gold nanoparticles (GNPs) was developed for Pb(2+) detection. The DNA capture probe was self-assembled onto the surface of the modified electrode for hybridizing with the guanine-rich (G-rich) aptamer probe and for forming the DNA double helix structure. When Pb(2+) was added in, the DNA duplex unwound and formed a stabilized G-quadruplex (G4) due to the Pb(2+)-induced G-rich DNA conformation. Also, methylene blue (MB) was selected as the G4-binding indicator. Compared with previous Pb(2+) sensors, the proposed sensor had better sensitivity, because the modified MWCNTs/GNPs could provide a large surface area and good charge-transport capacity to dramatically improve the DNA attachment quantity and sensor performance. The sensor could detect Pb(2+) in a range from 5.0 × 10(-11) to 1.0 × 10(-14) M, with a detection of 4.3 × 10(-15) M.

Background Irritable bowel syndrome (IBS) is common and difficult to treat and its pathogenesis is closely related to gut microbiota. However, differences in gut microbiota of patients in different regions make it more difficult to elucidate the mechanism of IBS. We performed an analysis of gut microbiota composition and functional prediction in Chinese patients with diarrhea-predominant IBS (IBS-D). Methods Fecal samples were obtained from 30 IBS-D patients and 30 healthy controls (HCs) in Nanchang, China. Using 16S gene sequence profiles, we analyzed the abundance of dominant microbiota at different taxonomy levels. Based on 16S information, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to predicting the function of gut microbiota. Results Compared to HCs, gut microbiota richness but not diversity was decreased in IBS-D patients. The abundant phyla Firmicutes, Fusobacteria and Actinobacteria decreased significantly, and Proteobacteria increased significantly in IBS-D patients. PICRUSt indicated that function expression of gut microbiota in IBS-D patients was up-regulated in metabolism of cofactors and vitamins, xenobiotics biodegradation and metabolism, and down-regulated in environmental adaptation, cell growth and death. Conclusions Compared with the normal population in China, IBS-D patients are characterized by complex and unstable gut microbiota, which may influence inflammation and metabolism of the host.

The present research was performed to clarify the changes of denitrifying genes (nirK, nirS, and nosZ) abundances under different physico-chemical parameters through evaluating the relationships between the genes abundances and parameters during agricultural waste composting. The genes abundances were determined by real-time quantitative PCR (qPCR). The correlations between physico-chemical parameters and denitrifying genes abundances were analysed by regression analysis. qPCR results showed that the nosZ gene abundance was higher than that of nirK and nirS genes. The nirK gene abundance was higher than nirS gene indicating that nitrite reducers with Cu-containing enzyme encoded by nirK gene were more of importance than those with cytochrome cd1 nitrite reductase encoded by nirS gene in the nitrite reduction step. Regression analysis suggested that (1) nirK gene abundance was correlated with pile temperature following quadratic model; (2) nirS gene abundance was linearly correlated with pile temperature and concentration of NH4 (+), while correlated with concentration of NO3 (-) and pH following inverse and quadratic model respectively; (3) nosZ gene abundance was quadratically correlated with pH and linearly correlated with water soluble carbon (WSC).

Background Early recurrent spontaneous abortion (ERSA) is a common condition in pregnant women. To prevent ERSA is necessary to look for abortion indicators, such as hormones and proteins, in an early stage. Methods Thirty patients with ERSA were enrolled in the case group. In the control group, we recruited 30 healthy women without a history of miscarriage undergoing voluntary pregnancy termination. The differentially expressed proteins in the serum were identified between the two groups using PRM and iTRAQ. Results Seventy-eight differentially expressed proteins were identified. Using GO functional annotation and KEGG pathway analysis, we detected that the most significant changes occurred in the pathway of Fc gamma R-mediated phagocytosis. Meanwhile, using PRM, we identified three proteins that were closely related to abortion, B4DTF1 (highly similar to PSG1), P11464 (PSG1), and B4DF70 (highly similar to Prdx-2). The levels of B4DTF1 and P11464 were down-regulated, while the level of B4DF70 was up-regulated. Conclusions CD45, PSG1, and Prdx-2, were significantly dysregulated in the samples of ERSA and could become important biomarkers for the prediction and diagnosis of ERSA. Larger‑scale studies are required to confirm the diagnostic value of these biomarkers.